Abstract Every day, individuals with acute serious illness face critical decisions about their medical care and use of life- sustaining treatments. These decisions regarding resuscitation, invasive procedures, or artificial nutrition are the key determinants of whether an individual will survive with functional limitations or transition to palliative care and end-of-life. While these decisions occur across the spectrum of disease, individuals with acute neurological disease such as stroke face several unique challenges due to the unexpected onset of disease, reliance on surrogate decision makers, and variability in outcome. Stroke is the 5th leading cause of death and a leading cause of adult disability in the US. There is currently dramatic variability in the use of life-sustaining treatments after stroke, with up to 40% of early mortality attributable to withdrawal of life-sustaining treatment. We have identified substantial inconsistencies in how physicians estimate and communicate stroke prognosis, raising the possibility that these communication differences may be in part responsible for the considerable variability observed in stroke end-of-life treatment. These inconsistencies may also be responsible for mismatches between patient values and the treatment plan. Currently, there is a critical gap in our understanding of how to help surrogates make treatment decisions consistent with patient values while minimizing adverse effects on the surrogate. Decision support tools, specifically recommended in the 2010 Affordable Care Act, have been shown to improve the quality of decisions and reduce burden on the decision maker in multiple clinical settings, yet almost none have focused on use of life-sustaining treatments in acute serious illness such as stroke. We propose a comprehensive frame shift in how the health care team and surrogates collaborate on decisions regarding life-sustaining treatments for acute illness, by developing a tailored web-based stroke decision support intervention based on a well-established theoretical framework for decision support. This web-based tool will be developed for surrogate decision makers to use during the acute stroke hospitalization, with the goals of facilitating high quality patient-centered decisions and minimizing adverse effects on the surrogate. The project aims are 1) To develop a tailored web-based decision support intervention to prepare stroke surrogates to make decisions on use of life sustaining treatments; and 2) To pilot test the tailored decision support intervention in surrogate decision makers of hospitalized stroke patients. Key features of the tool will include an advanced statistical prognostic calculator that presents customized outcome data in a tailored and accessible fashion; an exercise to assist the surrogate in clarifying values most important to the patient, and questions to ask the health care team to empower surrogates to communicate more effectively. Information obtained in this R21 is critically important to the development of a novel tool that can be tested in a future definitive R01 study in order to better match treatment plans to patient wishes, reduce adverse outcomes among surrogates, and limit unwanted variability in end-of life treatment.